KB5077800 (OS Build 20348.4650): Windows Server 2022 Out-of-Band Update - January 17, 2026
Out-of-band cumulative update for Windows Server 2022, releasing January 17, 2026, at OS build 20348.4650. Fixes Remote Desktop sign-in failures introduced by the January 2026 security update.
Summary
This is an out-of-band (OOB) cumulative update for Windows Server 2022, released on January 17, 2026, at OS build 20348.4650. It incorporates all fixes from the January 13, 2026 security update (KB5073457) and adds a targeted fix for Remote Desktop sign-in failures. Source: Microsoft Support
Improvements and fixes
- Remote Desktop sign-in fix: After installing the January 2026 security update (KB5073457), some users encountered sign-in failures when establishing Remote Desktop connections. This affected authentication steps across various Remote Desktop applications on Windows, including the Windows App. This OOB update resolves that failure.
Known issues
WSUS does not display synchronization error details
Symptom: After installing KB5070884 or any later update, Windows Server Update Services (WSUS) no longer displays synchronization error details within its error reporting interface. This functionality was temporarily removed to address the Remote Code Execution vulnerability CVE-2025-59287.
Workaround: Microsoft has not listed a workaround or resolution for this issue at the time the page was last updated.
Apps might become unresponsive when saving files to cloud-based storage
Symptom: After installing this update, some applications may become unresponsive or produce unexpected errors when opening or saving files to cloud-based storage services such as OneDrive or Dropbox. In certain Outlook configurations where PST files are stored on OneDrive, Outlook may hang and refuse to reopen unless the process is forcibly terminated or the system is restarted. Users may also notice missing sent items or previously downloaded emails being re-downloaded.
Workaround: This issue is addressed in KB5078136.
Some devices with Virtual Secure Mode enabled might fail to shut down or hibernate
Symptom: After installing this update, some Secure Launch-capable PCs with Virtual Secure Mode (VSM) enabled are unable to shut down or enter hibernation. Instead of shutting down or hibernating, the device restarts unexpectedly.
Workaround: This issue is addressed in KB5075906.
How to get this update
Before you install: Microsoft now ships the latest servicing stack update (SSU) combined with the latest cumulative update (LCU) in a single package. This release includes the Windows Server 2022 servicing stack update KB5074428 (version 20348.4640). Because the SSU is bundled with the LCU, the SSU cannot be removed from the system after installation.
Installation channels:
- Windows Update / Windows Update for Business: The update is available through the standard Windows Update channel.
- Windows Server Update Services (WSUS): Available via WSUS; consult the Microsoft Update Catalog option for details.
- Microsoft Update Catalog: A standalone package is available directly from the Microsoft Update Catalog. Note that this cumulative update includes updates for AI components; however, those AI components apply only to Windows Copilot+ PCs and will not install on standard Windows PCs or Windows Server.
Removing the LCU: If you need to remove the LCU after installing the combined SSU and LCU package, use the DISM /Remove-Package command with the LCU package name as the argument. You can identify the package name by running DISM /online /get-packages. Running wusa.exe with the /uninstall switch against the combined package will not work because the package contains the SSU.
Frequently asked questions
Why was this update released out-of-band rather than on Patch Tuesday?
Microsoft issued this update outside the regular monthly release cycle to deliver a targeted fix for Remote Desktop sign-in failures introduced by the January 13, 2026 security update (KB5073457). Out-of-band releases address high-priority issues that cannot wait until the next scheduled Patch Tuesday.
Does this update replace or include the January 2026 security update?
Yes. KB5077800 is cumulative and includes all fixes from the January 13, 2026 security update (KB5073457) in addition to the new Remote Desktop fix. If you install this OOB update, you do not need to separately install KB5073457.
Is the servicing stack update included, and does it need to be installed separately?
The servicing stack update KB5074428 (version 20348.4640) is bundled directly with this cumulative update. You do not need to install it separately. Once the combined package is installed, the SSU portion cannot be removed from the system.
How should admins handle the WSUS error-detail issue introduced by this update?
Microsoft temporarily removed synchronization error detail display in WSUS to mitigate the Remote Code Execution vulnerability CVE-2025-59287. Admins should monitor the Windows release health dashboard and the Windows Server 2022 update history page for resolution information as it becomes available.
